Welcome To The Underground
by SwiftAuditore
Summary: Update: Just to let you know i am in the process of rewriting this fanfiction i will keep a copy of the chapters of the previous version if you wanted to continue let me know. Two ordinary friends from our world fall into the world of Undertale. Will they find a way back to their world? Will they want to by the end? Also how did they come to be in the Undertale world to begin with?
1. Chapter 1 The Skeleton Bros

**SwiftAuditore: hey swifters I've had a re-read of my Undertale fanfiction and I have decided to rewrite the chapters to make them better I've started with chapter 1 and I will move on to the other chapters. You will have to put up with this one chapter while I take my time to rewrite the other chapters as well as working on my other stories. This will also give me time to work out what to do about Chara.**

 **Disclaimer: I don't own anything or anyone that belongs to Undertale it belongs to Toby Fox**

"Speech"

 _Thoughts_

 _ **Written words**_

 **Chapter 1 The Skeleton Bros**

I have just gotten back home from getting some needed supplies from the shop which the bags with the supplies are in my black leather messenger bag after finishing my recording session with my band my acoustic guitar case on my back when I hear a strange sound which is coming from my bedroom. I grabbed the baseball bat prop and I made my way to my bedroom and I held onto my guardian angel necklace as I walk to keep calm.

As soon as I went into the room I raised the bat in a horizontal position to block the fighting staff that was swung my way. I managed to block each attack that was swung at me. I am holding the bat against the staff when a piece of cloth is put over my mouth and nose. I struggled to get it off however eventually I breathed in causing me to blackout.

I let out a groan as I come to stretching my arms out when I open my eyes where I noticed that I am no longer in my home but outside and on the top of a mountain. I sit up and I remembered that Cleo my Bengal kitten and Indigo my snowshoe Siamese kitten I saved when Cleo and Indigo was a few days old at the time snuck into my messenger bag and breathed a sigh of relief when I see that they are both fine. Cleo and Indigo climbed out of the bag up my body and settled on my shoulders and I closed my messenger bag and stood up.

I looked around and I saw my friend lying on the floor not far from me so I made my way over to her and I crouched carefully and shook my friend's shoulder to wake her up. She jolted up nearly knocking Cleo from my shoulder.

"Are you alright Luanne?" I question

"Apart from a slight headache, I'm fine how are you Arietta?" Luanne replied massaging her head in an attempt to get rid of her headache while I respond to her question by telling her that I'm fine.

"Arietta do you know where we are?" Luanne asks I stood up from my crouch carefully and walked around to work out where we exactly are and I stop at a sign and read it causing me to gasp.

"What does the sign say Arietta?" Luanne asks

"The sign says Mt Ebott turn away now those that climb this mountain never come back Mountain Climbers Organisation" I read out

"We must be in the world of Undertale because I was putting finishing touches to a drawing for my next project when a cloth is put on my mouth and I struggled to get free however I failed in the end, though how we ended up in Undertale I have no idea. How did you wind up here?" Luanne exclaims and I explain what I remember before waking up here.

Luanne stood up and we walked around being careful to not fall into the hole as we are adjusting to where we are, we sat down at various times trying to figure out a way back to our world.

"Luanne I think that maybe the way back to our world is to fall down the hole which leads to the underground and maybe along the way we will find a way back home," I say

"I think you are right, I don't think we will find the answer just standing here anyway" Luanne agrees and we make our way to the hole and tripped on a vine and went tumbling down and into the hole.

I open my eyes seeing the blue sky I stood up at the same time Luanne did and I checked myself for any injuries and Luanne did the same and luckily we got no injuries from the attack. We walked off the flowers and down the hallway and through an archway and we see a golden flower with a face on it.

"H-Howdy! I'm Flowey. Flowey the Flower! What are your names?" the flower introduced himself

"My name is Arietta and this is my friend Luanne" I introduce myself and Luanne to be polite

"Hmmm… You're new to the underground aren'tcha? Golly, you both must be so confused. Someone ought to teach you how things work around here! I guess little old me will have to do. Ready? Here we go" Flowey initiated a battle with us and two hearts appeared mine which is turquoise colour and is in a diagonal position instead of vertical position and Luanne's heart which is purple. Flowey looks at my soul and gains a confused expression but changes to a neutral face after a few seconds.

"See that heart? That is your SOUL, the very culmination of your being! Your SOUL starts off weak but can grow strong if you gain a lot of LV. What's LV stand for? Why, LOVE, of course! You want some LOVE, don't you? Don't worry, I'll share some with you!" Flowey spins out white pellets around him. "Down here, LOVE is shared through... little white... "Friendliness pellets." Are you ready? Move around! Get as many as you can!" he continued and spun the pellets in the direction of our hearts we tried to dodge them but we failed because we didn't get the hang of moving our hearts out of the way in time.

"You idiot! In this world, it's kill or BE killed. Why would ANYONE pass up an opportunity like this!?" Flowey exclaims with a demonic grin and surrounded Luanne's heart and my heart and exclaimed "Die!" before sending the bullets closer.

Before the bullets could touch our hearts Flowey is sent flying by a fireball and we are instantly healed from the damage Flowey made. "What a terrible creature, torturing such a poor, innocent youths. Ah, do not be afraid, I am TORIEL, caretaker of the RUINS. I pass through this place every day to see if anyone has fallen down. You two are the first and second humans to come here in a long time and you two are the first teens to come here. Come! I will guide you through the catacombs." Toriel explains and leads us up some stairs and into a room.

Toriel explained the ruins and that you need to solve puzzles to get to the next room. She took us through a few rooms then gave us both a mobile phone and left us alone. We waited a while for her until we got anxious and bored so we decided to carry on through the ruins. On the way Toriel called us on the phone and asked if we liked butterscotch or cinnamon and answered that we liked butterscotch. Not long after that she rang again asking if we didn't dislike Cinnamon that we wouldn't turn our nose up if we found some on our plate and we answered that we liked Cinnamon as well.

Once we reached Toriel's house we see Toriel walk round a tree and she sees us and comes over to us and checks us over.

"We are sorry for leaving the room when you asked us to wait we got anxious then bored in that order" I speak

"It's ok since you both are fine" Toriel exclaims and leads the way to her home and lets us inside her home. We ended up in her living room

"My name is Arietta and this is my friend Luanne we are sorry that we forgot to introduce ourselves when we first met you" I say with Luanne agreeing and apologizing as well.

"It's ok now the pie is ready so if you two would have a seat please and I will get the pie" Toriel exclaims and we sit down at the table and we ate the Pie. She showed us to a room and apologized for their only being one however we told her that it was fine. I ended up getting the bed on Luanne's insistence.

Over the course of a week Luanne and I explored the entirety of the ruins and currently Luanne and I are in our room which now has two beds, Luanne and I see Toriel as a second mother. We are currently going through my bag while Cleo and Indigo are feeding. We are placing things into two piles which are one to keep and one to throw away and once we had finished sorting those piles out we disposed of the pile that we don't need to keep and moved on to sorting the pile to keep in order of what they are.

I pull a demon tail and demon horns that I once used for a Halloween video for my channel. "Luanne it's been a week since we fell down here and Frisk hasn't shown up yet. Why don't you stay here in the ruins and keep an eye out for Frisk and I will leave the ruins" I exclaim

"That's a good idea but how are you going to protect yourself?" Luanne asks

"By putting the demon horns and tail on as well as bringing my wings out I will look like a monster" I reply

"Let's go talk to Toriel about the idea" Luanne says and we leave the room to find her and we found her in the living room and we explained our idea to her leaving Frisk out of the explanation and she liked the idea and asked me to change so I went back to the bedroom Luanne and I share I put the demon tail in securely, pull my wings out and stretch them and put the demon horns on and I made my way back to the living room being careful to not move my wings.

"That is a really good disguise my child" Toriel says and Luanne agrees Toriel leaves the room for a short while and she returned and led me to the exit of the ruins and opened the door she and Luanne wished me luck, Luanne promises to look after Cleo and Indigo for me and I walk out of the ruins and Toriel closes the door behind me.

I started walking down the path shivering from the cold I move around the branch and continue walking when I heard a snapping sound do I turned around and saw a broken branch now lay on the ground no one else is there so I turn around and keep waling until I hear footsteps approaching me so I stop at a bridge.

"Human…. don't you know how to greet a new pal? Turn around and shake my hand" I turned around and took his hand and a fart like sound let out.

"Heheh… the old whoopee cushion in the hand trick. It's always funny. Anyways, you're a human, right? That's hilarious. I'm sans. Sans the skeleton" he says

"My name is Arietta it's nice to meet you Sans" I greet

"I know that you are human because Toriel told me that you are a human disguising yourself as a monster. Good disguise though one question Arietta why do your wings look real?" Sans inquired while answering the unspoken question.

"Because they are real sans and I have them because when I turned four *sniff* I watched my parents being attacked it left them in a coma for a few years" I start but I was interrupted

"Your parents were attacked by other humans?" Sans inquired

"Yeah they were anyway after they were killed I was grabbed and thrown against a wall and I blacked out when I woke up I was strapped to a table and a man injected blood of a Devil inside of me and it changed my hair colour to red, gave me these wings and gave me abilities. A year later I managed to escape and I had trouble trying to control my abilities and the devil whose blood was injected into me appeared before me and taught me to control my abilities and showed me how to use my wings and how to hide and bring them out. She was curious as to how I remained human and not turned into a devil like her and she did some tests and we found out that I'm still human because I have enough of my parent's blood" I explain

I kept sniffing and tears started to fall and sans pulls me into a hug and I just cry from all the emotional pain that was brought up while I told him that story. "Hey, it's alright you are safe now, have you told anyone that story other than me?" Sans speaks and strokes my hair and keeps his arms around me.

It took a while but I finally calmed down. "No sans you are the first person I told that story to" I answer he just looked at me shocked and asked if I would hurt any monsters "Sans I don't want to hurt anyone it's not who I am and after what I went through I don't want to cause anyone pain" I exclaim

"I'm sorry I asked but I had to know" Sans states

"It's fine, Sans I understand" I speak smiling at him

"c'mon let's go through those bars my bro made them too wide to stop anyone" Sans exclaims and we walk through the bars and we stopped outside by a lamp. "Speaking of my bro here he comes" Sans speaks and he walked into the area and he was about to speak but stopped when he saw me.

"SANS WHO IS THIS" he questions

"Papyrus this is Arietta and she told me she has nowhere to stay" Sans speaks

"ARIETTA YOU CAN STAY WITH MY BROTHER AND I UNTIL YOU ARE ABLE TO GET YOUR OWN HOME. SANS… IT'S BEEN EIGHT DAYS AND YOU STILL HAVEN'T RECALIBRATED YOUR PUZZLES WHAT HAVE YOU BEEN DOING?" Papyrus exclaims

"Take it easy bro... I've gotten a ton of work done. A Skele-ton" Sans exclaims causing me to laugh finding it funny.

"That was very humerus" I exclaim once I managed to stop laughing sans and Papyrus stare at me.

"UGGH NOT YOU TOO!" Papyrus exclaims with a groan causing sans and I to laugh at the expression on his face.

"Good one Arietta" Sans exclaims and they led me to their home in Snowdin. They let me crash on their couch.

 **SwiftAuditore: Hey swifters this is it for this chapter and regarding my other stories I have writer's block for my flames of compassion story and I am working on another chapter for my other story but it is going slow.**


	2. Chapter 2 W D Gaster

**SwiftAuditore: Hey swifters and welcome to chapter 2 this is my revamped version with many changes to it. If there are any problems in this chapter let me know in a review and I will change it.**

 **Disclaimer: I don't own anything or anyone that belongs to Undertale it belongs to Toby Fox**

"Speech"

 _Thoughts_

 _ **Written words**_

 **Chapter Two W D Gaster**

The day after sans and Papyrus let me stay with them, sans took me to Grillby's after Papyrus said he was going to Undyne's house to train. Sans introduced me to Grillby and everyone in the pub as being new to Snowdin. I played a song with my guitar after one of the monsters in the pub requested it.

Currently, I am having a burger with sans after performing at Grillby's when a monster kid runs up to me and asks me "Can you play Undyne's theme" he hands me some music sheets and I look through them.

"Give me a few days to learn it and I will be able to play the theme" I respond after I finished my meal and sans finished his drink he led me to a secluded part of Snowdin and leant against a tree.

"Sans are you alright?" I ask

"I'm fine" Sans immediately responded

"No you aren't sans, it's not healthy to keep things bottled up," I say

"Alright since you trusted me enough to tell me your past, do you know the multiverse theory?" sans inquires

"Yes, I've heard of it why?" I reply

"this isn't the first time I've seen a human in snowdin recently but it is usually a kid, not a teen and I've seen time after time the kid reset sometimes they are peaceful and sometimes they have gone on a killing spree. This is the first time I've seen you show up. I can't keep watching the kid go on a killing spree and reset again. Every time I get settled on the surface I wake up here in snowdin. It has to stop I can't take it anymore" Sans explains

"Sans I will help you find a way to stop the endless resets. Sans, I'm an adult human I know I look younger than I am" I say as I pull sans into a hug to comfort him. After that, we started walking to the entrance of the ruins.

Sans knocks on the door "knock knock" sans asks

"Who's there?" Toriel asks

"ya," Sans says

"Ya who?" Toriel asks

"yahoo! i'm just as psyched to see you" sans says the punchline and Toriel laughs and I smile happy to hear Toriel's voice

"hey toriel I brought a friend of ours with me" sans says

"Hi, Toriel how are you doing?" I greet Toriel and we talked about what's been going on recently for us and sans thankfully didn't interrupt it.

"knock knock," sans says

"Who's there," Toriel asks

"nanna," Sans says

"Nanna who?" Toriel asks

"nanna your business, that's who" sans says and Toriel and I laugh we spent a long time telling jokes to each other. Sans and I said goodbye to Toriel and vice versa and we went back to Sans' and Papyrus' house.

"Brother you and Arietta are late" Papyrus stated

"Sorry bro we lost track of time" sans says and with that we had dinner and Papyrus is getting better at cooking every day soon he may make something edible. After watching an episode on TV staring Mettaton I appreciated the show because I understood his desire to entertain his viewers as well as trying to keep hope for monster kind. Sans and Papyrus went to their rooms after bidding me goodnight and once sans had entered his room I laid down on the couch and went to sleep.

I took in my surroundings to notice that I am chained to a wall which caused my heart to beat rapidly as I tried to get free even more so when I saw the man that had attacked my family walk over to me with a sadistic grin on his face.

I screamed for help as he started hitting me when everything around me froze as a skeleton with scars on his face appears. He has an angry look on his face as he took in the scene and soon everything around me went black and I am in my adult form again.

"Hi, my name is Arietta what's your name?" I ask

"My name is W D Gaster but you can call me Gaster, could you tell me who that man that was hurting you is?" he introduced himself

"It's a long story, one I'm not quite up to explaining just yet'" I answer

"Longer than the cut-down version you gave my son sans. I know that because I saw and heard it happen. I was the previous royal scientist and due to an accident at work, I fell into my creation. It led to me being stuck in the void and with your help, I think I can get out of it" Gaster says

"Alright I will help you get out but how can I help you get out of the void?" I ask

"Get Sans to take you to the lab that is behind this house the blueprints that are in it are mostly right they just need one adjustment which is a small gear replacing the broken middle gear and the machine should work enough for me to come back" Gaster voices

"Ok I will tell sans about it" I agree

"Would you mind if I took a look at your soul?" Gaster inquires

"I don't mind" I voice and Gaster pulls my soul from my body

"Interesting, this is connected with your past with the way it is diagonal and your soul being turquoise means that it is a mix of patience and Integrity, when I come back would you tell me your past and not the cut down version, you should really tell someone about it" Gaster says I look at Gaster for a few seconds _He is right I need to tell someone the full details of what happened and not the cut down version I usually give_

"Ok I will tell you but only you" I finally say

"When I have finally gotten out of the void we will talk" Gaster exclaims and with that I wake up to find sans standing in front of me.

"are you alright I heard you whimpering?" sans asks

"I'm fine I started having a nightmare but a tall skeleton who introduced himsel Gaster appeared and stopped the nightmare we had a chat" I reply and I see sans stiffen and he is locked on me

"What did you two talk about?" he asks

"Gaster told me with my help he can get out of the void he said to get you to take me to the lab behind this house, that the blueprints that are in it are mostly right they just need one adjustment which is a small gear replacing the broken middle gear and the machine should work enough for him to come back. After that our conversation went in another direction" I answer sans seems to brighten a bit hope appearing in his eyes.

"let's do it now" sans says and takes my arm and teleports into the lab, he walks over to the machine and takes the covering off the machine and he passed me the tools to open the machine when it is open I remove the broken gear and sans takes the gear and hands me a small gear and I put it where the broken gear was and I closed the machine and sans turned it on and after a few seconds the room is engulfed in a bright light.

When the light dimmed a tall skeleton with scars on his face is standing in front of sans and I, I could tell that it worked Gaster is out of the void and sans went to Gaster and hugged him who returned the hug. We went back into the house and sans went to his room and back to sleep while Gaster led me to his bedroom.

"Now Arietta could you tell me about your past now please" Gaster voices and I tell him the full story of my past and I had to take a deep breath during several points of the tale so I wouldn't break down. At the end of it I broke down and started crying Gaster pulled me into him and hugged me and removed the horns and tail and placed them on a table he ran his hands through my hair not saying a word just holding me close to him.

"Thanks" I exclaim and I pull away after several minutes went past and Gaster wiped the tears from my face.

"We should get some sleep" Gaster voices

"Yeah but I don't think I am going to be able to I will just have nightmares of my past" I say

"Why don't we share this bed perhaps having someone with you would help, do you want to give it a try?" Gaster suggests _it may just work and if it helps me get some rest I will give it a try_

"Alright it is worth a shot" I agree and I pull my wings in and Gaster took his coat off and hung it on a coat rack and got into bed next to me and he turned the light off and he fell asleep and though it took me several seconds I fell asleep as well.

I open my eyes to see that I am cuddled into Gaster and he has his arms wrapped around me in a protective hold I look at his face and notice how peaceful he looks while asleep. After a few seconds Gaster opens his eye sockets and notices out position we let go of each other and I sit up as Gaster gets out of bed.

"How did you sleep?" Gaster says while putting his coat on

"I slept better than I thought I would" I answer and I sit on the bed.

"Does Sans and Papyrus know about you being human? Even with the disguise with the horns, tail, and your wings?" Gaster asks

"I know that sans knows about me being human but I don't think Papyrus knows or if he does he hasn't let on that he does" I answer just then sans knocks on the door and Gaster opens the door and greets sans.

"Sans does Papyrus know about Arietta being a human but disguises herself as a monster?" Gaster asks

"No I don't think he does" sans replies

"Arietta why don't you go down with just your wings and we will tell him about you being human" Gaster suggests and I agree wanting Papyrus to know the truth. We left the room and went downstairs and Papyrus froze when he sees Gaster.

 **SwiftAuditore: this is the end of the rewritten version of chapter two. I'll see you swifters in the next chapter.**


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